redonkable/remarkable-linux
redonkable/remarkable-linux
1
0
Fork 0
Code Releases Activity

perf/abi: Document some more aspects of the perf ABI

Browse source 
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2015-08-28 14:06:07 +02:00 committed by Ingo Molnar
parent 73fdeb6659
commit b0e8787594
1 changed files with 98 additions and 19 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

117
include/linux/perf_event.h
View file

@ -140,27 +140,60 @@ struct hw_perf_event {
};
#endif
};
/*
* If the event is a per task event, this will point to the task in
* question. See the comment in perf_event_alloc().
*/
struct task_struct *target;
int state;
local64_t prev_count;
u64 sample_period;
u64 last_period;
local64_t period_left;
u64 interrupts_seq;
u64 interrupts;
u64 freq_time_stamp;
u64 freq_count_stamp;
#endif
};
/*
* hw_perf_event::state flags
* hw_perf_event::state flags; used to track the PERF_EF_* state.
*/
#define PERF_HES_STOPPED 0x01 /* the counter is stopped */
#define PERF_HES_UPTODATE 0x02 /* event->count up-to-date */
#define PERF_HES_ARCH 0x04
int state;
/*
* The last observed hardware counter value, updated with a
* local64_cmpxchg() such that pmu::read() can be called nested.
*/
local64_t prev_count;
/*
* The period to start the next sample with.
*/
u64 sample_period;
/*
* The period we started this sample with.
*/
u64 last_period;
/*
* However much is left of the current period; note that this is
* a full 64bit value and allows for generation of periods longer
* than hardware might allow.
*/
local64_t period_left;
/*
* State for throttling the event, see __perf_event_overflow() and
* perf_adjust_freq_unthr_context().
*/
u64 interrupts_seq;
u64 interrupts;
/*
* State for freq target events, see __perf_event_overflow() and
* perf_adjust_freq_unthr_context().
*/
u64 freq_time_stamp;
u64 freq_count_stamp;
#endif
};
struct perf_event;
/*
@ -210,7 +243,19 @@ struct pmu {
/*
* Try and initialize the event for this PMU.
* Should return -ENOENT when the @event doesn't match this PMU.
*
* Returns:
* -ENOENT -- @event is not for this PMU
*
* -ENODEV -- @event is for this PMU but PMU not present
* -EBUSY -- @event is for this PMU but PMU temporarily unavailable
* -EINVAL -- @event is for this PMU but @event is not valid
* -EOPNOTSUPP -- @event is for this PMU, @event is valid, but not supported
* -EACCESS -- @event is for this PMU, @event is valid, but no privilidges
*
* 0 -- @event is for this PMU and valid
*
* Other error return values are allowed.
*/
int (*event_init) (struct perf_event *event);
@ -221,27 +266,61 @@ struct pmu {
void (*event_mapped) (struct perf_event *event); /*optional*/
void (*event_unmapped) (struct perf_event *event); /*optional*/
/*
* Flags for ->add()/->del()/ ->start()/->stop(). There are
* matching hw_perf_event::state flags.
*/
#define PERF_EF_START 0x01 /* start the counter when adding */
#define PERF_EF_RELOAD 0x02 /* reload the counter when starting */
#define PERF_EF_UPDATE 0x04 /* update the counter when stopping */
/*
* Adds/Removes a counter to/from the PMU, can be done inside
* a transaction, see the ->*_txn() methods.
* Adds/Removes a counter to/from the PMU, can be done inside a
* transaction, see the ->*_txn() methods.
*
* The add/del callbacks will reserve all hardware resources required
* to service the event, this includes any counter constraint
* scheduling etc.
*
* Called with IRQs disabled and the PMU disabled on the CPU the event
* is on.
*
* ->add() called without PERF_EF_START should result in the same state
* as ->add() followed by ->stop().
*
* ->del() must always PERF_EF_UPDATE stop an event. If it calls
* ->stop() that must deal with already being stopped without
* PERF_EF_UPDATE.
*/
int (*add) (struct perf_event *event, int flags);
void (*del) (struct perf_event *event, int flags);
/*
* Starts/Stops a counter present on the PMU. The PMI handler
* should stop the counter when perf_event_overflow() returns
* !0. ->start() will be used to continue.
* Starts/Stops a counter present on the PMU.
*
* The PMI handler should stop the counter when perf_event_overflow()
* returns !0. ->start() will be used to continue.
*
* Also used to change the sample period.
*
* Called with IRQs disabled and the PMU disabled on the CPU the event
* is on -- will be called from NMI context with the PMU generates
* NMIs.
*
* ->stop() with PERF_EF_UPDATE will read the counter and update
* period/count values like ->read() would.
*
* ->start() with PERF_EF_RELOAD will reprogram the the counter
* value, must be preceded by a ->stop() with PERF_EF_UPDATE.
*/
void (*start) (struct perf_event *event, int flags);
void (*stop) (struct perf_event *event, int flags);
/*
* Updates the counter value of the event.
*
* For sampling capable PMUs this will also update the software period
* hw_perf_event::period_left field.
*/
void (*read) (struct perf_event *event);